Various systems have been developed to monitor the surface deflection of highway and airport pavements that occurs as a vehicle (e.g., truck, airplane) travels over the pavement. The surface deflection of pavements refers to the elastic deformation of the pavement. Such deformation, which may not be visible to the naked eye, may indicate early pavement damage requiring repairs. Since repairing pavement as opposed to pavement reconstruction, such as when damage becomes visible to the naked eye, is much cheaper, the deflection of pavement is measured as frequently as possible in order to repair damaged pavement before it becomes extensive requiring reconstruction.
Currently, systems used to detect pavement deflection utilize vehicles that are very slow moving, which may result in disrupting traffic, such as on a highway. Furthermore, such systems use indirect measurements which require calibration thereby providing less accurate measurements. Additionally, some systems rely upon Doppler (relative velocity) measurements, an example of an indirect measurement, making them unsuitable for measuring the deflection of certain types of pavements.
As a result, there is not currently a system that is able to accurately measure pavement deflection that utilizes a vehicle that travels at the velocity of traffic without relying on indirect measurements.